The Russian Air Force recently received the first four of several hundred updated Mi-8 helicopters. The decision to buy these was made two years ago and the order was placed in 2013. There are several updated Mi-8 models involved. The ones just delivered are the Mi-8AMTSh. This is described as a "combat assault helicopter" that can be equipped with missiles and autocannon, as well as carry up to 37 troops or four tons of cargo. Among the many improvements are a new engine and mechanical components that are more efficient and easier to maintain. Compared to older Mi-8s the Mi-8AMTSh can go longer (2,000 flight hours compared to 1,500) between overhauls and has a longer service life (35 years versus 25). Operating costs are at least 25 percent less and a lot of this is due to more modern electronics and the incorporation of continuous system monitoring systems found in most new automobiles. Another new model, the Mi-8MTV5-1, has new engines that enable it to operate at high and hot altitudes (which are difficult conditions for helicopters).
Rather than seek out and buy a new medium transport helicopter design, Russia is continuing the decades old policy of upgrades and improvements to the original Mi-8 design. This has made the Mi-8 a reliable and affordable choice for armed forces around the world and in Russia itself (which currently has about 600 Mi-8s in the air force alone). Currently there are over 8,000 Russian helicopters in service in 110 countries worldwide. The most common Russian model is the Mi-8 and its export variants, the Mi-17.
The basic Mi-8 is a twin-engine helicopter that is a contemporary of the U.S. UH-1 of the 1960s. But the Mi-8/17 is still in production and is the most widely exported (a quarter of the 12,000 made) helicopter on the planet. The Mi-8 is about twice the size and weight of the UH-1 but only hauls about 50 percent more cargo. However, the Mi-8 has a larger interior and can carry 24 troops, versus a dozen in the UH-1. The UH-1 was replaced by the UH-60 in the 1980s, while the Mi-8 just kept adding better engines and electronics to the basic Mi-8 frame. The UH-60, while weighing ten tons (compared to UH-1's 4.8 tons), could carry as much as the 13 ton Mi-8. But the Mi-8 costs about half as much as a UH-60 and the larger interior is popular with many users.